Valve mechanism for dishwasher

ABSTRACT

In a pump housing having a valve for controlling the flow of pressurized fluid therethrough, a valve element is pivotally mounted in the housing, adjacent the outlet, for pivotal movement within the housing between a first position opening the outlet and a second position closing the outlet. At an intermediate position, between the first and second positions, the valve element is poised to be responsive to fluid flow through the housing whereby the valve element is caused to move to the second position in response to pressure of fluid flowing through the housing. The valve mechanism also includes a first biasing means that urges the valve element toward its normal first position, a second biasing means adapted to urge the valve element from the first position to the intermediate position, and releasable holding means that normally acts to prevent the second biasing means from moving the valve element to the intermediate position until the latching means is actuated to release the second biasing means. The releasable latching means is preferably a bimetallic electric resistance element that responds thermally and deflectively contracts to thereby release the second biasing means.

United States Patent [72] Inventor BobbyJ.Ralston Louisville, Ky. [21 Appl. No. 69,394 [22] Filed Sept. 3, 1970 [45] Patented Jan. 11, 1972 [73] Assignee General Electric Company [54] VALVE MECHANISM FOR DISHWASHER [56] References Cited UNITED STATES PATENTS 3,498,327 3/1970 Dicken 137/625.44 2,788,190

4/1957 Jamieson Primary Examiner-Henry T. Klinksiek Attorneys-George C. Atwell, Francis H. Boos, Jr., Frank L.

Neuhauser, Oscar B. Waddell and Joseph B. Forman ABSTRACT: In a pump housing having a valve for controlling the flow of pressurized fluid therethrough, a valve element is pivotally mounted in the housing, adjacent the outlet, for pivotal movement within the housing between a first position opening the outlet and a second position closing the outlet. At an intermediate position, between the first and second positions, the valve element is poised to be responsive to fluid flow through the housing whereby the valve element is caused to move to the second position in response to pressure of fluid flowing through the housing. The valve mechanism also includes a first biasing means that urges the valve element toward its normal first position, a second biasing means adapted to urge the valve element from the first position to the intermediate position, and releasable holding means that normally acts to prevent the second biasing means from moving the valve element to the intermediate position until the latching means is actuated to release the second biasing means. The releasable latching means is preferably a bimetallic electric resistance element that responds thermally and deflectively contracts to thereby release the second biasing means.

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INVENTOR.

B055! 3'... RALSTON \S ATTORNEY slsaalszz PATENTEU JAM 1 i972 SHEET 2 OF 2 INVENTOR. BOBBY J. RALSTO N H\S ATTORNET VALVE MECHANISM FOR DISHWASHER BACKGROUND OF THE INVENTION This invention relates generally to a pump mechanism and more particularly pertains to valve mechanism structure in combination with a housing in an automatic dishwashing machine.

An automatic dishwasher conventionally has a complete cycle of operation which includes several admissions of water, each of which is followed by a wash or rinse operation wherein the water is recirculated through a wash chamber. After a suitable length of time, the recirculation is terminated and the water is discharged from the dishwasher into the household sewer system. The recirculation and the discharge or pumpout of the water from the machine is accomplished by a pump.

In one type of dishwasher a pair of pumps is used, each driven by its own motor. One of the pumps provides a recirculation and the other is actuated to accomplish the discharge of washing liquid from the dishwasher. Another common typeof dishwasher also utilizes a pair of pumps and both are driven by the same motor. Usually an electrically reversible motor is employed in the latter type ofdishwasher so that the recirculation pumping is accomplished when the motor is actuated to rotate its shaft in one direction, and the discharge operation is obtained when the motor is reversed.

In US. Pat. No. 3,367,368, issued to Thomas E. Jenkins on Feb. 6, 1968, and titled Outlet Valve For Dishwasher Pump, structure is disclosed for a dishwasher that employs a single pump to perform both the recirculation and discharge functions, and uses a motor to drive the pump that operates by rotating its shaft always in one direction. The Jenkins arrangement for the use ofa single pump and a single motor, which involves the use of a pump housing having two outlets with a valve mechanism to control the flow of fluid from the housing, is a highly reliable dishwasher pumping system that is relatively inexpensive to manufacture. The present invention comprehends an improved and still less expensive construction for the valve mechanism in the type of pumping apparatus disclosed and claimed in the Jenkins patent.

SUMMARY OF THE INVENTION Broadly described, the present invention includes a pump housing having a major recirculation outlet for fluid under pressure to be discharged therethrough and a valve element adapted to be selectively movable, preferably by a pivotal arrangement, between a first open position permitting discharge through the outlet and a second closed position preventing such discharge. The valve mechanism includes releasable latching means, means for holding the valve element normally in the first position, and biasing means adapted to move the valve element from the first position to an intermediate position when the releasable latching means is automatically actuated by the dishwasher timer control mechanism. When in its intermediate position, the valve element is disposed to be responsive to pressure of fluid flowing through the pump housing whereby the fluid pressure urges the valve element from the intermediate position to the second or closed position. When the fluid pressure holding the valve element at the closed position diminishes to less than a preselected magnitude, a second biasing means returns the valve element from the closed position to the open position so that the outlet is again unobstructed and fluid may be discharged therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view, partially cut away to show details, of an automatic dishwasher employing a pump valve mechanism in accordance with the present invention;

FIG. 2 is a fragmentary view, partially cut away to show details, ofa pump housing and valve arrangement employed in the dishwasher of FIG. 1, and showing the valve element disposed at its normal first or open position relative to the main discharge outlet of the pump housing;

FIG 3 is a view of the pump housing of FIG. 2 taken from the opposite side thereof as compared to FIG. 2;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and particularly to FIG. I. there is illustrated an automatic dishwasher 10 having an outer cabinet 11 defining therein a wash chamber 12. Within the wash chamber 12 are dish-supporting racks l3 and 14 which are adapted to receive and support dishes or other items to be washed with the chamber 12. A closure member or door 15 is provided in one wall of cabinet 11 and it is arranged to be pivotal by means of a hinge means 16 whereby access to the wash chamber 12 is provided. When the door 15 is in its downward or open position, rack 13 can be partially withdrawn outwardly from the wash chamber by means of a slide and roller arrangement 17 that supports the rack 13 from the inner sidewalls of thecabinet 11. Rack 14 is also adapted to be withdrawn whereby it extends from the wash chamber 12 and through the access opening by means of a roller 18 which tracks upon a ledge surface 19 provided on each side of the cabinet 11.

The wash chamber 12 has a floor or bottom wall 20 which gradually slopes to a low point 21 near the center of the dishwasher. Disposed below the low point 21 is a sump 22 which may be formed integrally with bottom wall 20 or with an opening through the bottom wall 20. Projecting upwardly from the bottom wall 20 near the center of wash chamber 12 is a pedestal 23 which rotatably supports a reaction-type spray device 24. The spray device 24 is provided with a plurality of orifices 25 through which wash fluid, either heated water and detergent constituting a wash liquid or water constituting a rinse liquid, is ejected to effectuate a wash action upon items supported in racks 13 and 14. At least one of the orifices 25 is adapted to provide a reaction force in response to a directed jet of wash liquid passing therefrom that imparts rotation to the spray device 24.

A motor-pump assembly 26 provides the flow of liquid to the spray device 24. The motor-pump assembly 26 includes an electric motor 27 that drives an impeller (not shown) carried within a pump housing 28. A flexible boot or conduit 29 interconnects sump 22 with the inlet of pump 28 whereby liquid from the wash chamber 12 is directed to the pump for recirculation back to the spray device 24. As shown in FIG. 3, the pump housing 28 has an inlet 31 for receiving liquid from the conduit 29 (FIG. 1 Carried centrally within the housing 28 is a rotatable shaft 32 on which the pump impeller (not shown) is mounted. The impeller is driven by the motor 27 shown in FIG. 1. The pump housing 28 also has a first discharge outlet or major recirculation outlet 33 that feeds pumped liquid to the spray device 24, and a second or drain outlet 34 through which liquid is pumped at the end of each wash cycle, to the household sewer system.

The valve mechanism of the present invention includes a valve element 35 mounted for pivotal movement within the housing 28. The valve element includes a first sealing member 36 for closing off the outlet 33 and a sealing member 37 for closing off the drain outlet 34. The sealing members 36 and 37 are supported by a pivotal arm 38 that extends from the sealing members and terminates as a shaft extending through the pump housing 28. An outer shaft end 38a of the arm 38 projects through the housing, and has an outer end portion that extends through and outwardly from a fixed planar base or platform 39. The platform 39 is attached to the housing 28 whereby it is stationary thereto.

The outwardly projecting shaft end 380 has a pivotal plate, hereafter referred to as a valve plate 40, fixed thereto whereby the valve plate 40 and the valve element 35 will pivot as a unit. The valve plate 40 is disposed to pivotally rotate in a plane parallel to the fixed platform 39 whereby pivotal movement of the valve plate 40 results in corresponding movement of the valve element 35. The valve plate 40 has an opening or slot 41 provided therethrough, and a rigid rod or link 42 has an end pivotally attached through the opening 41.

As shown in FIGS. 2, 4, and 5, the link 42 extends from the valve plate 40 to a drive plate 43 pivotally mounted on a shaft 44 extending outwardly from the platform 39. The drive plate 43 has an arcuate slot 45 for receiving an end of the link 42 in a loose sliding arrangement therein. Also mounted on the platform 39 is a bimetallic electrical resistance element 48 having a fixed end 49 that is mounted to the platform 39 by suitable rivets and insulators The element 48, more commonly referred to as a bimetal, is a well-known device comprising a pair of laminated strips of different metals or alloys having different coefficients of expansion whereupon, in response to heat, the bimetal will thermally respond by deflecting to a bowed configuration such as shown in FIG. 5'. Heat may be provided to the bimetal 48 by conducting a current therethrough whereby its own electrical resistance results in the transformation of electrical energy to heat energy which causes the body of the bimetal to deflect. The outer or loose end of the bimetal 48, as shown in FIG. 6, is provided with an opening 50 therethrough to engage a tooth-shaped portion 51 of the pivotal drive plate 43.

When the valve element 35 is in its normal or first position, the various components thereof are disposed as shown in FIG. 2, with the outlet 33 open whereby recirculation of liquid to and from the washer chamber 12 (FIG. 1) will occur when the motor 27 is energized to pump liquid through the housing 28. When the valve element 35 is disposed in this first position, its sealing member 37 is disposed to close off the drain outlet 34. Also, the bimetal 48 is in its normal deenergized state, and the tooth 51 of the plate 43 is engaged in the opening 50 of the bimetal 48.

Reorientation of the valve element 35 from the position shown in FIG. 2 occurs in response to a timed electrical impulse transmitted by the dishwashing machines timer control (not shown) to the bimetal 48. This action normally occurs after the recirculation step in the operational cycle ofthe machine, which may be a wash step or a rinse step dependingon whether or not fresh detergent has been added to the recirculated liquid. The bimetal 48 serves as a releasable latching means. When it is energized by the timer control whereby it deflects away from the drive plate 43 so that the tooth-shaped portion 41 moves out of the opening 50, a biasing means in the form of a spring 53 pivots the drive plate 43 on its shaft 44 in a clockwise direction as viewed in FIG. 2. The spring 53 is anchored to the platform 39 by a pin 54 and has its other end attached along the outer edge of the drive plate 43 by a pin 55. When the drive plate 43 is oriented as shown in FIG. 2, the spring 53 is stretched whereby, when the drive plate 43 is released from the element 48, contraction of the spring 53 causes the plate 43 to pivot. This pivotal action of the drive plate 43 results in a knee portion 56 of the drive plate 43 hitting against a shoulder 57 of the valve plate 40. The valve plate 40 is thereby rotated counterclockwise as viewed in FIG. 2. This counterclockwise movement of the valve plate 40 pivots the valve element 35 from the first position shown in FIG. 2 to an intermediate position shown in FIG. 5. When the valve element 35 is disposed at its intermediate position, it is extending across and into the pumped flow of liquid. The force of the pumped liquid against the element 35 acts to further pivot it to the second or closed position as shown in FIG. 4 whereby the element 35 obstructs the outlet 33 so that the liquid is thereafter pumped outwardly through the drain outlet 34.

Movement of the valve element 35 from the intermediate position to the second position where it obstructs the outlet 33 has the effect of stretching a second biasing or holding means in the form of a spring 58, that acts as a means of storing energy for a later operation of the valve element 35. The spring 58 has one end fixed to the platform 39 at a pin 60 and its other end fixed to a point on the under surface of the valveplate 40 by means of a pin'59 located along the outer edge of the plate 40.

As soon as substantially all liquid is discharged through the drain outlet 34 or when deenergization of the motor 27 driving the pump impeller occurs, the pressure within the pump housing 28 will diminish and relieve the liquid pressure holding the valve element 35 in the closed position across the outlet 33. The tension of the spring 58 is such that it is too weak to contract when the liquid force is being exerted against the valve element 35 to hold it in the closed position across the outlet 33 but is sufficient, when the liquid force diminishes below a predetermined magnitude, to pivotally retract the valve plate 40 in a clockwise direction as viewed in FIG. 4 whereby the valve element 35 is returned to the first position so that its sealing member 37 closes off the drain outlet 34.

It should be noted that when the valve element 35 pivoted in response to pressure of liquid within the housing 28, from the intermediate position shown in FIG. 5 to the second or closed position shown in FIG. 4, the movement of the element 35 resulted in a corresponding movement of the valve plate 40 to the position shown in FIG. 4. This movement of the valve plate 40 was translated through the link 42 whereby the drive plate 43 was rotated counterclockwise as viewed in FIG. 5 to the position shown in FIG. 4 with the result that the tooth portion 51 reengaged through the opening 50 of the bimetal 48. Thereafter when liquid pressure within the housing 28 diminished whereby the spring 58 took over" and returned the valve element to the recirculation position, consequent rotation of the valve plate 40 in unison with the valve element 35 had no effect on the drive plate 43 inasmuch as the link 42 slid the length of the arcuate slot in the drive plate 43 to the position shown in FIG. 2.

The present invention provides a dependable valve mechanism for a pump that is uniquely adaptable for use in a dishwasher of the type using a nonreversible motor to drive a pump that serves both to recirculate liquid and to drain liquid from the machine. As compared to the Jenkins US. Pat. No. 3,367,368, mentioned previously herein, the present invention provides a unique valve arrangement that represents a significant cost savings over the employment of a timer-controlled solenoid in combination with linkage to control the valve element ofthe mechanism.

As will be evident from the foregoing description, certain aspects of the invention are not limited to the particular details of construction of the example illustrated, and it is anticipated that various other modifications or applications will occur to those skilled in the art. It is therefore intended that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of the invention.

I claim:

1. A valve for a fluid pump in which an outlet of the pump is closed in response to fluid pressure against a pivotal valve element, including:

a. means for holding the valve element in a first normally open position out of the flow path of the pumped fluid,

b. a drive plate movable to overcome the holding means and thereby move the valve element into the path of the pumped fluid,

c. biasing means for so moving the drive plate,

d. means for normally latching the drive plate whereby it is prevented from being moved by the biasing means, and

e. means for releasing the latching means at a predetermined time whereby the drive plate will so move in response to the biasing means that it extends across the path of the pumped fluid.

2. The invention of claim 1 wherein said latching means includes an electrical currentresponsive element.

3. The invention of claim 1 wherein said latching means includes a thermally responsive element.

4. The invention of claim 1 further comprising a second outfluid through said housing so that the fluid tends to urge let in said housing adjacent said first mentioned outlet, and said valve element fully into said second position, said valve element being operative to close off said second f, a second spring d t d to urge aid valve element to id (milet when Said first Position first position when the flow of fluid urging said valve ele- 5. In a pump for use in an automatic dishwasher:

a a pump housing,

b. at least first and second outlets in said housing,

c. a valve element adapted to be pivotal between a first position and a second position whereby it closes one of said outlets when in said first position and closes the other of 10 said outlets when in said second position,

d. a first spring normally biasing said valve element toward said second position,

e. one of said outlets being positioned relative to the flow of ment to said second position diminishes below a predetermined magnitude,

g. releasable latching means normally preventing said valve element from being urged away from said first position, and

h. means for releasing said latching means.

6. The invention of claim 5 wherein said releasable latching means includes an electrical current responsive element. 

1. A valve for a fluid pump in which an outlet of the pump is closed in response to fluid pressure against a pivotal valve element, including: a. means for holding the valve element in a first normally open position out of the flow path of the pumped fluid, b. a drive plate movable to overcome the holding means and thereby move the valve element into the path of the pumped fluid, c. biasing means for so moving the drive plate, d. means for normally latching the drive plate whereby it is prevented from being moved by the biasing means, and e. means for releasing the latching means at a predetermined time whereby the drive plate will so move in response to the biasing means that it extends across the path of the pumped fluid.
 2. The invention of claim 1 wherein said latching means includes an electrical current-responsive element.
 3. The invention of claim 1 wherein said latching means includes a thermally responsive element.
 4. The invention of claim 1 further comprising a second outlet in said housing adjacent said first mentioned outlet, and said valve element being operative to close off said second outlet when in said first position.
 5. In a pump for use in an automatic dishwasher: a. a pump housing, b. at least first and second outlets in said housing, c. a valve element adapted to be pivotal between a first position and a second position whereby it closes one of said outlets when in said first position and closes the other of said outlets when in said second position, d. a first spring normally biasing said valve element toward said second position, e. one of said outlets being positioned relative to the flow of fluid through said housing so that the fluid tends to urge said valve element fully into said second position, f. a second spring adapted to urge said valve element to said first position when the flow of fluid urging said valve element to said second position diminishes below a predetermined magnitude, g. releasable latching means normally preventing said valve element from being urged away from said first position, and h. means for releasing said latching means.
 6. The invention of claim 5 wherein said releasable latching means includes an electrical current responsive element. 